Cold planers, sometimes also called road mills, scarifiers, or surface treatment machines, rotate a drum with cutting bits over a work surface. These machines are designed to prepare or treat a surface like a road, pavement, or soil. A motor connected to the drum by way of a drive train and gear box rotates the drum so that the cutting bits alter the work surface. The cutting bits contact the work surface and cause it to be broken into pieces and removed. The forces exerted by the cutting bits on the work surface can be significant, and as a result the cutting bits can wear.
Since the cutting bits are subject to wear, they need to be regularly inspected and replaced. In order for the drum to be inspected, it needs to be lifted off of the work surface and selectively rotated at a slow speed and for small angles of rotation. The motor described above is set up to drive the drum somewhat more continuously, forcefully, and quickly than is useful for drum inspection. A separate auxiliary drive system is needed to rotate the drum for inspection and servicing.
One attempt to address this issue is described in U.S. Pat. No. 7,644,994 filed by Busley et al., and issued on Jan. 12, 2010. The '994 patent describes a milling device having an auxiliary drive located inside of an associated drive belt. The auxiliary drive includes a friction roller that can engage the drive belt or a drive pulley connected to the milling drum. By using a friction roller, the '994 patent reduces the risk of turning the work drum too forcefully.
Although the '994 patent provides a way of rotating the work drum for inspection and service, the design may also have drawbacks. The auxiliary drive of the '994 patent being located inside the drive belt may present issues when attempting to retrofit older machines. On machines that were not originally designed with an auxiliary drive, the area inside of the drive belt may not be suitable for installing an auxiliary drive such as that of the '994 patent. Additionally, mounting the auxiliary drive motor inside the belt drive may expose the motor to high levels of vibration and dust, which can reduce the service life and reliability of the auxiliary drive.
The present disclosure is directed toward one or more of the problems set forth above.